The present invention relates to bixin colorant compositions and self-coloring food casing, preferably cellulosic food casing. Self-coloring casings have colorant coatings which are transferable to the encased foodstuff during processing.
In some areas of the world it is customary to eat sausages, particularly small diameter (circumference &lt;115 mm) sausages, which have been colored on the sausage surface by application of a colorant. Historically, different colorants have been applied to sausage surfaces by various means. For example, sausages have been colored by smoking with gaseous or liquid wood smoke, by dipping peeled sausages into a vat containing a colorant, by spraying or dipping encased sausages with a casing permeable liquid dye, and also by stuffing sausage meat into casings having their interior surfaces coated with a transferable colorant. In the United States, coloring of sausage products encased in natural animal casings in which the colorant was retained in the casing was authorized by the United States Department of Agriculture (U.S.D.A.) at least as early as 1922. Use of self-coloring cellulosic casings made with synthetic colorants was approved by the U.S.D.A. in 1947 and such casings have been commercially available since 1948. In different regions of the world, different colors range in popularity and some colorants may impart flavor as well as color. In certain areas orange and orange-red colored sausages are extremely popular.
In Brazil, a very popular sausage is made by dipping cooked and peeled sausages in a vessel containing heated, water-soluble annatto colorant (norbixin in water). Residence time of the sausage with the colorant in the vessel is dependent upon the concentration and temperature of the colorant and may be e.g. for a period of 5 minutes or less at high temperature or for a longer period of time (up to 20 minutes or longer) at elevated but relatively lower temperatures to produce the desired coloration. This water-soluble annatto colorant is fixed to the surface of the sausage by contact with an acid, typically phosphoric acid.
This method has several disadvantages e.g. time, labor, maintenance and equipment costs associated with separate equipment for dipping or otherwise coating the sausage with colorant, and energy costs, particularly associated with heating the above colorant. Also, the mechanisms for providing a continuous process of introducing uncolored sausages and removing colored sausages may result in broken or abraded sausages, and the residence time in the vat varies from sausage to sausage causing undesirably and perceptibly different shades of color. It is highly desirable that the colored sausages have a uniform color not only with respect to each individual sausage, but also within the same lot of sausages produced, and between lots produced from one day to the next, or from week to week, or month to month and so on. Uniformity of color is desired by the customer.
Also, the long residence time of cooked and peeled sausages in the heated annatto is believed to enhance the possibility of increased microbial growth and decreased shelf life of the colored sausages. Furthermore, annatto colorant is expensive and application by coating or dipping in a vessel or vat requires that the vessel or vat be periodically cleaned and the colorant recycled to remove by-products formed by the dipping procedure such as meat pieces and accumulated fats. All of this requires additional expense and time for equipment and maintenance. During use the colorant must be frequently replenished as it is depleted or the color intensity of the coated sausages will become undesirably light. Also, the colorant must be periodically replaced because it becomes less effective after constant use at elevated temperatures. In addition, the application of acid such as phosphoric acid to further bind the annatto colorant to the meat may require an additional separate vat and related equipment including equipment to facilitate both processing and recycling.
Various patents disclose coloring or flavor compositions including compositions which contain annatto, norbixin or bixin.
U.S. Pat. No. 4,285,981 (Todd, Jr. et al.) issued in 1981 and discloses liquid seasoning compositions useful for flavoring or coloring foods and beverages. The disclosed compositions are purportedly dispersible in both oil and water, and consist essentially of lecithin, tartaric acid esters of mono- and di-glycerides, and one or more edible flavorants or colorants such as annatto extract, bixin or norbixin. The colorants may be used in an amount between 1-20% by weight of the composition.
U.S. Pat. No. 4,699,664 (Hettiarachchy et al.) issued in 1987 and discloses a process for preparation of natural pigment complexes having improved stability against oxygen, heat, light and moisture, and which are water soluble under acidic conditions. In the disclosed process, a pigment such as bixin, norbixin or betanin is combined with at least one inorganic polyvalent cation source and with at least one hydrocolloid having at least one carboxyl group in an aqueous alkaline medium. The hydrocolloid may be modified cellulose, or derivatives or salts thereof. Compositions are also claimed in which a polyvalent cation is associated with both the pigment and the hydrocolloid through their respective carboxyl groups.
U.S. Pat. No. 4,877,626 (Ande et al.) which issued in 1989 discloses that a mixture of liquid smoke, caramel and optionally bixin (or annatto) may be used to color raw meat.
U.S. Pat. No. 4,759,936 (Best et al.) which issued in 1988 discloses a food coloring composition which may comprise annatto, an oil (preferably of triglycerides), an emulsifier (preferably of monoglycerides, diglycerides or mixtures thereof), and a gelling agent of carrageenan and water. The gelled emulsion may also comprise glycerol. A gelling agent of guar gum and gelatin is also suggested.
U.S. Pat. No. 5,079,016 (Todd, Jr.) which issued on Jan. 7, 1992 discloses color stabilized carotenoid pigment compositions which consist essentially of an annatto, tomato, carrot, marigold, or synthetic carotenoid in combination with a nonionic surfactant which is selected from the group of:
a) mono and diglycerides of fatty acids; PA1 b) polyglyceride esters of fatty acids; PA1 c) mono and diglyceride esters which are further esterified with a dibasic organic acid which is either a citric or lactic acid; PA1 d) acetylated mono and diglyceride esters further esterified with a dibasic organic acid which is either a citric or a lactic acid; PA1 e) sorbitan esters of fatty acids; PA1 f) propylene glycol esters of fatty acids; and PA1 g) lecithin.
U.S. Pat. No. 5,139,800 (Anderson et al.) which issued Aug. 18, 1992 discloses a composition comprising a dispersed phase consisting essentially of a colorant (or a colorant dissolved or dispersed in an oil-immiscible medium) and a continuous phase consisting essentially of an oil or edible fat, wherein the composition is colorless when applied to food, but causes browning upon cooking. The colorant may comprise water soluble annatto, beet powder, carmine or caramel among others. The oil may be a vegetable oil or partially hydrogenated vegetable oil among others. The composition may further comprise an emulsifier such as mono-and diglycerides. The composition may also include a viscosifying agent in an amount of from about 0.01 to about 1 percent by weight. This viscosifying agent may be hydroxypropylcellulose, carboxymethylcellulose, methyl cellulose, agar, pectin, starch, gelatin, xanthin gum, or guar gum among other agents. The composition may also include a film forming agent, preferably hydroxypropylcellulose or methyl cellulose. Other suitable film forming agents are said to include zein, arabinogalactan, and carboxymethylcellulose among others. Also, the composition may further comprise an oil soluble colorant such as oil soluble annatto in a concentration of from about 0.01 to about 2 percent of the composition. The composition is disclosed as being suitable for application to foodstuffs including poultry, beef, fish, cheese, pork, fruits and vegetables.
Self-coloring food casings used in the processed food industry are generally thin-walled tubing of various diameters, typically prepared from cellulose. In general, these food casings have multifunctional uses in that they may be employed as containers during the processing of the food product encased therein and also serve to transfer colorant to the encased foodstuff to color the surface of the finished product. Typically the encased foodstuff is sausage made from beef, pork, chicken, turkey or other meats. In the sausage meat industry, the preparation of various types of sausages including wieners or frankfurters in a variety of sizes usually involves removing the casing from around the processed meat prior to final packaging. These sausages, from which the casing is usually removed prior to sale, are generally processed in nonfiber-reinforced (nonfibrous) cellulose casing. However, larger diameter sausages such as salami are frequently sold with the casing left on. These sausages are usually packaged in fiber-reinforced (fibrous) cellulosic casing or nylon casing. Self-coloring casing transfers colorant to the sausage surface during processing so that the sausage surface remains colored after removal of the casing.
In the manufacture of nonfibrous regenerated cellulose sausage casings which are self-coloring, viscose is typically extruded through an annular die into a coagulating and regenerating bath to produce a tube of regenerated cellulose. This tube is subsequently washed, plasticized e.g. with glycerine, impregnated with a water-soluble, casing-permeable colorant, and dried e.g. by inflation under substantial air pressure. After drying, the self-coloring casing is wound on reels and subsequently shirred on high-speed shirring machines, such as those described in U.S. Pat. Nos. 2,984,574, 3,451,827 3,454,981; 3,454,982; 3,461,484; 3,988,804 and 4,818,551. In the shirring process, typically lengths of from about 40 to about 200 or more feet of casing are compacted (shirred) into tubular sticks of between about 4 and about 30 inches. These shirred casing sticks are packaged and provided to the meat processor who typically causes the casing sticks to be deshirred at extremely high speeds while stuffing the deshirred casing with a meat emulsion. The meat can be subsequently cooked or pasteurized and the casing removed from the meat processed therein with high-speed peeling machines. The resulting peeled sausage is colored by the colorant which has transferred from the casing to the surface of the sausage during cooking or pasteurization. Uncolored nonfibrous casings are made in a similar fashion, but without the color additive steps.
For fibrous casing, a process of manufacture similar to that for nonfibrous casing is employed, however, the viscose is extruded onto one or both sides of a tube which is usually formed by folding a web of paper so that the opposing side edges overlap. In production of fibrous casing the viscose impregnates the paper tube where it is coagulated and regenerated to produce a fiber-reinforced tube of regenerated cellulose. The fibrous or paper reinforcement is generally utilized in tubular casing having diameters of about 40 mm or more in order to provide dimensional stability particularly during stuffing with meat emulsion.
Production of both nonfibrous and fibrous casing is well-known in the art and the present invention may utilize such well known processes and casings.
Cellulosic casings are typically humidified to a level sufficient to allow the casing to be shirred without undue breakage from brittleness, yet humidification must be at a level low enough to prevent undue sticking of the casing to the shirring equipment e.g. the mandrel during the shirring operation. Often a humectant is employed to moderate the rate of moisture take up and casing swelling, to produce a casing which during the shirring operation has sufficient flexibility without undue swelling or stickiness. Typically, a lubricant such as an oil will also be used to facilitate passage of the casing through the shirring equipment e.g. over a shirring mandrel.
It has been useful to lubricate and internally humidify cellulose casings during the shirring process by spraying a mist of water and a stream of lubricant through the shirring mandrel. This is an economical, fast and convenient way to lubricate and/or humidify the casing to increase the flexibility of the casing and facilitate high speed shirring without undue detrimental sticking, tearing or breakage of the casing.
Cellulosic food casings suitable for use in the present invention will preferably have a moisture content of less than about 100 wt. % based upon the weight of bone dry cellulose (BDC). The term "bone dry cellulose" as used herein refers to cellulose such as regenerated, derivatized or nonderivatized cellulose and/or paper which has been dried by heating the cellulose in a convection oven at 160.degree. C. for one hour to remove water moisture. In the formation of cellulosic casing an extruded cellulosic film forms what is known as gel stock casing having a high moisture content in excess of 100 wt. % BDC. This gel stock casing is unsuitable for stuffing with food such as meat emulsion, e.g. to form sausages, because it has insufficient strength to maintain control of stuffing diameter and prevent casing failure due to bursting while under normal stuffing pressure. Gel stock casing is typically dried to a moisture level well below 100 wt. % (BDC) which causes the cellulose to become more dense with increased intermolecular bonding (increased hydrogen bonding). The moisture level of this dried casing may be adjusted, e.g. by remoisturization, to facilitate stuffing. Such remoisturization or moisture adjustment, e.g. by drying to a specific level, for nonfibrous casing is typically to a level with a range of from about 5 to about 40 wt. % BDC. Small diameter nonfibrous casing, prior to shirring, will have a typical moisture content of about 10-20 wt. % BDC, and such small diameter nonfibrous casing when shirred will have a moisture content that has been adjusted to between about 20 to 40 wt. % BDC.
For fibrous casing, casing is commercially produced having a moisture content ranging from about 4 wt. % BDC to about 70 wt. % BDC. Typically, premoisturized, ready-to-stuff, fibrous casing which does not require additional soaking or moisturization will have a moisture content of from about 26 to about 70 wt. % BDC. Also, commercialized is fiber-reinforced casing having a moisture level between about 4 to about 25 wt. % BDC. Such low moisture casing will be soaked prior to stuffing by a food processor.
Also, thermoplastic casings such as polyamide casings made from monolayer or multilayer structures containing a nylon layer are known. Nylon casings comprising a blend of nylon with polyester are known as are multilayer casings of nylon with ethylene polymers or copolymers.
In the formation of skinless (casing removed) frankfurters, sausage proteins coagulate, particularly at the sausage surface, to produce a skin and allow formation of a liquid layer between this formed skin and the casing as described in U.S. Pat. No. 1,631,723 (Freund). In the art the term "skinless frankfurter" is understood to mean that the casing is or is intended to be removed and that such casing may be removed because of formation of a secondary "skin" of coagulated proteins on the surface of the frankfurter. This secondary skin forms the outer surface of the so called "skinless frankfurters". Skin formation is known to be produced by various means including the traditional smoke curing with gaseous smoke, low temperature drying, application of acids such as citric acid, acetic acid or acidic liquid smoke or combinations thereof. Desirably, this secondary skin will be smooth and cover the surface of the frankfurter. Formation of a liquid layer between the casing and the frankfurter skin facilitates peeling and relates to the meat emulsion formulation, percent relative humidity during the cooking environment, subsequent showering and steam application to the chilled frankfurter.
Also, application of certain types of coatings to the inside wall of food casings may afford improvement in the release characteristics of the casing from the encased sausage product. Use of peeling aids or release coatings has helped to overcome peelability problems associated with process variables. Following cooking, cooling and hydrating, peeling aids such as water-soluble cellulose ethers help release the casing from the frankfurter skin by formation of a peeling enhancing layer between the casing and the frankfurter skin.
In U.S. Pat. No. 3,898,348, the coating of internal surfaces of cellulose sausage casings with a homogeneous mixture of a water-soluble cellulose ether peeling aid and a pleat release agent selected from animal, vegetable, mineral and silicon oils and alkylene oxide adducts of partial fatty acid esters was taught. The coating is applied to the casing surface in a composition such that the pleat release agent is present in a proportion of about 0.1 times the weight of the water soluble cellulose ether and up to about 0.5 milligrams per square inch of casing surface. Such mixtures have excellent meat release characteristics and can also effectively protect the casing from "pinholing" failures occasioned by pleat locking. Easy peeling casings utilizing the release coating have found broad commercial acceptance and are presently in use in casings throughout the world.
U.S. Pat. No. 4,137,947 to Bridgeford discloses a method of improving the meat release (peelability) of cellulose sausage casings by the application of a meat release coating to the internal surface thereof. The coating comprises a homogeneous admixture of a water-soluble cellulose ether, the partial fatty acid ester of sorbitan or mannitan and a water-soluble polyalkylene ether of the type R(--OC.sub.2 H.sub.4 O).sub.n --H wherein R represents long chain alkyl radicals having 8 to 16 carbon atoms and n is an integer from 4 to 40. An aqueous coating composition containing the water-soluble cellulose ether, partial fatty acid ester and polyalkylene ether is typically applied to the interior of the sausage casing prior to shirring.
The foregoing peeling aid coatings have been utilized with varying degrees of success to provide cellulosic casings capable of being peeled on high speed machine peelers. Generally such cellulosic casings either with or without peeling aid coatings have an approximately neutral pH with pH values typically falling within a range of about 5.9 to 8.6.
Use of various transferable colorants on food packaging including cellulosic casing has been known for some time.
Self-coloring casings are disclosed in U.S. Pat. Nos. 2,477,767; 2,477,768 and 2,521,101. These casings are designed to transfer color to the sausage surface. Such casings are generally either coated or impregnated with food grade water-soluble dyes and have also been made commercially available with nontransferable black or white or colored opaque stripes. Also, liquid smoke impregnated casings are known to transfer liquid smoke to the surface of sausages encased therein transfering a flavorant or colorant and also causing a browning reaction on the sausage surface. Casings having either nontransferable or transferable indicia, logos, words are also known e.g. U.S. Pat. Nos. 1,959,978; 2,301,564 and 4,917,924.
U.S. Pat. Nos. 2,477,767 and 2,477,768 (Remer) which both issued in 1949 and which are now expired were assigned to Transparent Package Company (Teepak) and disclose regenerated cellulose sausage casings uniformly treated with a transferable, edible natural coloring matter. Included in a list of such materials is annatto. The colorant may be applied with glycerine and/or other polyhydric alcohols or vegetable oil.
French Patent Publication No. 2,258,798 discloses use of cellophane coated with an annatto derived dye such as Na or K norbixin in combination with a xanthene-type food dye to color a meat surface.
PCT Publication No. WO 91/03917 published in 1991 and discloses a microwavable container having a coating of a transferable browning agent such as annatto. This disclosure states that the browning agent may be applied in microwave transparent material in an aqueous binder. The microwave transparent material purportedly may be any food grade plastics or cardboard material known for use in microwave containers such as cardboard (generally with a protective layer such as a polyester, polypropylene or nylon film). Suitable aqueous binders are said to include gelatin, starch, starch derivatives, gums and fat based binders such as palm kernel oil. Typical amounts of browning agent are disclosed as being applied suspended in a binder at a concentration of 0.1 to 2% by weight with drying for 6 to 10 minutes at 60.degree. C. to achieve physical stability so that the coating does not flake or rub off. It is further suggested that other additives may be present in the coating including flavorings such as sweeteners and emulsifiers such as lecithin to facilitate dispersion.
Also, shirred cellulosic casings have been obtained from the marketplace which are believed to have had a nonuniform coating of bixin, phosphate and vegetable oil on the inner surface of the casing. Such casings transfer color to sausages, but disadvantageously an undesirably large amount of the color may be wiped off unless the sausage is treated with a separate phosphoric acid solution. Also, the color transferred from these casings tends to be nonuniform varying from light to dark orange with distinct lines of color associated with shirring folds and edges of flattened and reeled casing. Peeled sausages made in such casing continue to require contact with colorant in a dip tank and a subsequent acid dip to provide a product having commercially acceptable color uniformity and intensity. The vacuum packaged frankfurters made with this casing exhibit an undesirable colored purge. These casings in the shirred form also have poor coherency.
In certain parts of the United States orange to orange-red sausages are very popular. Typically these colored sausages are made using self-coloring casings dyed with synthetic colorants such as coal tar dyes which have been approved by government regulation for use on food. These dyes, which are typically known as F.D. & C. dyes are typically applied to cellulosic casings by dipping gel stock casing into a tank containing an aqueous mixture of glycerine and the F.D. & C. dyes. A combination of water-soluble red and yellow F.D. & C. colorants produce an orange color and these colorants permeate and migrate through the wall of cellulose casing dipped therein so that colorants applied to the exterior of gel stock casing migrate through the casing to the interior surface. The gel stock casing is then dried, forming semi-finished casing. Semi-finished casing may be shirred directly in a continuous operation from the gel stock casing or it may be wound on reels and subsequently formed into shirred sticks and used conventionally.
Disadvantageously, these F.D. & C. dyes upon transfer to the surface of a sausage have a tendency to penetrate into the sausage and migrate away from the surface towards the center of the sausage. Such migration is undesirable, because the customer prefers that only the coagulated proteinaceous surface skin be colored, and not the interior of the sausage. Also, where blends of these colorants are used such migration may occur at different rates and to different extents thereby producing a chromatographic effect where the sausage in cross-section may have different colors e.g. red, orange, yellow as well as the natural meat color, because of separation of constituent dyes of a blended colorant as the individual dyes migrate away from the sausage surface at different rates of speed.
Also, in some markets only natural colorants (derived from biological organisms), such as cochineal, turmeric, annatto and caramel are authorized by law and use of synthetic (fossil-fuel derived or nonbiologically derived) colorants such as coal tar dyes is not authorized. This is especially true for many South American and Asian markets where use of natural colorants derived from plants or animals are preferred by custom or law.
In addition, in the United States, from time to time certain F.D. & C. colorants have been removed from the list of governmentally approved colorants thereby creating customer apprehension regarding use of all such coal tar-derived colorants. There also exists a preference amongst many consumers for food colorants which are naturally derived from renewable plants or animals over synthetically derived colorants.
Natural colorants, such an annatto, either in the oil-soluble form of bixin or the water-soluble form of norbixin, are less stable than synthetic dyes and tend to oxidize in the presence of air or under light thereby causing fading and loss of color intensity. Also, natural colorants will vary in shading and color may change during processing. The color appearance of a natural colorant such as bixin or norbixin may vary from one sausage product to another depending upon such factors as sausage formulation and processing conditions including e.g. relative humidity and acid showering. Changes in pH of the colorant coating caused by process variations may produce pH based color changes.
Bixin is not soluble in water and also is not easily dispersed in water by itself. Attempts to disperse bixin (or bixin with oil) in water generally yield poor dispersions which have little or no affinity for cellulose films. Dispersions consisting of bixin in water, or bixin and oil in water, produce nonuniform, undesirably uneven coatings on cellulose casing which are commercially unacceptable.